it's fair to note that the Fediverse is much older than the AP protocol. It originally came up through a duo of protocols, OStatus and the Diaspora protocol.

Before Mastodon we had Status.net, Identi.ca, and GNU Social.

The Fedi will be celebrating its 15th year soon:

https://fediverse.party/en/post/fediverse-14-years-in-2022/